Gear-case for sprocket-and-chain drives



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0,13. HOLMES. GEAR CASE FOR SPROGKBT AND CHAIN DRIVES. No.'592,288.PatentecLOot. 26, 189-7.

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(No Model.) 3 SheetsSheet 2.

OQ.B.HOLMES.

GEAR CASE FOR SPROCKET AND CHAIN DRIVES. No. 592,288. w Patented Oct.26,1897.

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,(No Model.) I 3 Sheets-Sheet 3.

0.- B. HOLMES GEAR CASE FOR SPROGKET AND CHAIN DRIVES.

No. 592,288. Patented Oct. 26,1897.

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.NITED STATES ATIENT rion.

CHARLES B. HOLMES, OF MINNEAPOLIS, MINNESOTA.

SPECIFICATION forming, part of Letters Patent No. 592,288, dated October26, 1897. Application filed November 27, 1896. Serial No. 618,543. (Nomodel.)

citizen of the United States, residing at Minneapolis, in the county ofHennepin and State of Minnesota, have invented certain new and usefulImprovements in Gear Cases for Sprocket-'and-Ohain' Drives; and I dohereby declare the following to be a full, clear, and exact descriptionof the invention, such as will enable others skilled in the 'art towhich it appertains to make and use the same.

My invention has for its object to provide an improved gear-case forsprocket-and-chain drives especially adapted for use on safetybicycles.

To this end my invention consists of the novel devices and combinationsof devices hereinafter described, and defined in the claims.

My invention is illustrated in the accompanying drawings, wherein, likeletters referring to like parts throughout the several views-= Figure 1is a view in right side elevation showing a portion of a safety-bicyclewith my improved gear-case applied in'working position to thesprocket-and-chain drive thereof. Fig. 2 is a horizontal section takensubstantially on the line 02 m of Fig. 1. Fig. 3 is a transversevertical section taken substantially on the line m m of Fig. 1, but withthe driving-chain removed. Fig. 4 is a vertical longitudinal sectiontaken substantially on the line 00 x of Fig. 2. Fig. 5 is aviewcorresponding in the line of its section to Fig. 4, but showing theparts of the case removed from the machine and drawn apart or separatedfrom each other. Fig. 6 is a detail view, in longitudinal verticalsection, showing a portion of the rear hoodand case sections connectedthereto, some parts being broken away, and the said parts being viewedfrom the left side of the machine. Fig. 7 is a view corresponding toFig. 5, but'illustrating a slightly-modified form of certain parts ofthe gear-case .and'Figl 8 is a view corresponding in the line of itssection'to Fig. 7, but showing theparts of the case removed from themachine and drawn apart or separated from each other.

a small driven sprocket a Referring to the parts of the bicycle shown, aindicates the rear wheel, having the hub a mounted on the spindle a andprovided with a a a indicate, respectively, the rear forked ends, thebottom stays, and the crank-shaft hanger of the framework. a indicatesthe pedal crankshaft mounted, in said hanger a" and provided with adriving-sprocket a and pedals a; and a indicates the sprocket-chainrunning over the sprockets a and a all of which parts may be of theordinary standard construction.

Referring to the parts of my improved gearcase and directing attentionfirst to my preferred form illustrated in Figs. 1 to 6, inclusive, itwill be noted that when myimproved gear-case is applied in workingposition on the machine, as shown in Fig. 1, both of the sprockets andthe sprocket-chain are completely incased, so that it is practicallyimpossible for any dust or dirt to find their way into the interior ofthe case. In this preferred form 1) indicates what I may term a ,hoodfor the rear sprocket a This hood I) in horizontal cross-section isU-shaped, so as to embrace the front and sides of said sprocket, and thesides of the same are formed with open-ended slots 19, which pass andembrace the wheel-spindle a and permit the properadjustment of the sameto take up the slack of the chain, as will later more fully appear. A

. b 1)? indicate a somewhat similar but larger hood-section, which isadapted to embrace the sides and cover the rear portion of thedrivingsprocket'at The inner prong or side 12 of this hood 6 b isremovable from the othersection'of said hood, being held in placetherewith by means of small machine-screws b or otherwise. The outerprong of said hood b is provided with a central passage adapted to passthe pedal crank-shaft a and the removable inner side section b isprovided with a central passage formed by a projecting annular flange badapted to embrace the rightside end of the crank-shaft hanger a 'a'ndtobe firmly secured thereto by means of small machine-screws b.

As shown, the hood-sections b and b are rigidly connected together by achannel-shaped piece 12 which forms a cover or incasing section to theunder side of the upper section of the chain. Likewise the lowerportions of said hood-sections I) and Z1" may be rigidly connected bymeans of stub channel-sections b and b, projecting, respectively, fromsaid hood-sections, and a removable channel-piece b securable to saidstubchannels l) b, as shown, by means of small machine-screwsl) Thisremovable section b, when removed from the stub-sections b b", willpermit the case-sections so far described to be placed in workingposition, diagonally embracing the rightmember of the bottom stays a, asshown best in Fig. 2. To place these parts in working position, it is,however, necessary to remove the hood-section b from the section b andthe right pedal arm or lever a" from the crankshaft a". The first timethe gear-ease is placedin working position on the machine it is alsonecessary to remove the driving-sprocket a from working position, sothat the hood-section Z) may be secured on the crank-shaft hanger a, asshown; but after the said section b has once been placed in workingposition it will not again be necessary to remove the same either inremoving the other parts of the case or in placing the same in workingposit-ion, as it is only necessary to remove the screws 1), thusseparating said case-sections b and b. It will also be noted that thehoodsection Z), when secured in working position, serves as a supportfor the entire front end of the gear-case.

To form a cover or marginal incasing casesection for the hood and insidechain-covers or ineasing sections, I employ in my preferred formchannel-sections c, which are bent at their ends to conform to the outermargins of the hood-sections and are secured together at their rear endsby a hinged joint 0'. At their forward ends said sections 0 are adaptedto be secured together by means of a clamping device involvingbracket-irons 0 secured thereto, and a thumb-screw ciworking through oneof said brackets and having screw-threaded engagement with the other, soas to draw the forward ends of said section 0 tightly together and ontothe case-sections,with which they ongage when placed in workingposition.

To form a dust-tight joint between the inside ease-sections and what Ihave termed the parts are placed in working position, the flexiblepacking-strips 0 will be tightly pressed against the cooperatingmarginal shoulders I) of the said inside ease-scctions, thus, as isobvious, forming a tight joint therewith.

It is thought to be obvious from the foregoing description that themarginal cover or section 0 0 may be readily placed in working positionand removed. When the said marginal coveris removed, the chain may bereadily taken oif or placed in working position without removing anyother portions of the gear-case. By further removing the section Z1 suchaccess may be had to the inside or running face of the chain as may benecessary to apply graphite to the same, for example.

It is also very important to note that in virtue of the constructionshown and described the rear wheel maybe adjusted toward and from thecrank-shaft, so as to take up the slack of the chain without disturbingor readjusting the parts of the gear-case above described. To accomplishthis, it is only necessary to loosen the nuts a on the ends of therear-wheel spindle 0,

I also preferably employ adjustable slotclosing devices, which serve tokeep the slots Z) of the rear hood-section I) always closed regardlessof the adjustment of the rear wheel. As shown, the inside slot Z1 iskept closed by means of a sliding plate g, held in working position andadjust-ably movable in said slot by means of keeper-lugs g and providedwith a perforation which is adapted to pass the hub of thesprocket-wheel of. The outside slot Z) may likewise be also kept closedby means of an eccentric washer g on the spindle a, which is adapted tobe tightly clamped against the face of one of the ballbearing cones andthe inside of the outer prong of the rear hood I) by means of the nut a.It will be seen that this clamping action on the outer prong of the hoodI) also serves to securely hold the rear end of the gear-case in workingposition.

The construction illustrated in Figs. 7 and 8 is substantially the sameas that just de scribed, with the following exceptions: The forwardhood-section 7b is formed with a pair of stub channel-sections 72, whilethe rear hood-section Z) is formed with a pair of long channel-sections71 the forward ends of which are detachablysecurable to thestub-sections 7t by means of machine-screws 7L3. The prongs or sideplates of the hood h are provided with central shaft-passages 7t, fromwhich slots 7r are cut to the forward edges of said prongs. These slots7r may be closed by means of pivoted shields or cover 7L. IVith thislatter-described construction. it is possible to place the gear-case inworking position, without removing either the right pedal to ordriving-sprocket f, simply by an endwise movement of the section 7t 7t,with the slots 7r embracing the pedal crank-shaft, and then connectingthe stub-sections to the sections h after both of the said hoods havebeen placed in working position.

The efficiency of my improved gear-case is thought to be obvious fromthe foregoing description. It will be understood, of course, thatvarious alterations in the details of construetion may be made withoutdeparting from the spirit of my invention. For example, if the marginalcase-sections 0 care made sufiiciently flexible or spring-yielding theymight be formed of a single strip and the hinged joint cdispensed with,and the forward or sectioned ends of the same might be secured togetherby any suitable form of clamping device.

What I claim, and desire to secure by Letters Patent of the UnitedStates, is as follows:

1. A gear-case for a sprocket-andrchain drive, involving hood-sectionswith pronged disk-like sides that substantially cover the sides of thesprocket-wheels, channel-shaped inside case-sections, extending betweensaid hoods, and a channel-shaped marginal cover for said hoods andinside case-sections, formed by two hinged sections that are detachablysecurable at their free ends, substantially as described.

2. A gear-case for a sprocket-and-chain drive, involving the hood I)with slots b, the hood-section b with removable side b the insidecase-section b uniting said hood-sections 1) and b the stub-sections bb", respectively, on said hood-sections b and b the removable insidecase-section b and the outside marginal case-sections embracing andclosing the outer open margins of said aforenamed case-sections,substantially as described.

In testimony whereof I afiix my signature in presence of two witnesses.

CHARLES B. HOLMES.

lVitnesses:

O. F. KILGORE, F. D. MERCHANT.

